Question #105106
Consider the ideal I=<x³-1, 2x⁴+2x³+7x²+5x+ 5>in Q[x]
Find
p(x) belongs to Q[x]such that I=<p(x)> .
Is Q[x]/I is field ? Give reasons for your answer
1
Expert's answer
2020-03-16T14:51:55-0400

p(x)=(x31,2x4+2x3+7x2+5x+5)p(x)=(x^3-1,2x^4+2x^3+7x^2+5x+5) is the greatest common divisor of 

x31x^3-1 and 2x4+2x3+7x2+5x+52x^4+2x^3+7x^2+5x+5 .

Find p(x)p(x) according to Euclid's algorithm

2x4+2x3+7x2+5x+5:x312x^4+2x^3+7x^2+5x+5:x^3-1


2x4+2x3+7x2+5x+5x312x42x2x+22x3+7x2+5x+52x327x2+7x+7x2+x+1\begin{matrix} 2x^4+2x^3+7x^2+5x+5 &&&& |x^3-1 \\ 2x^4-2x &&&& 2x+2\\ &&2x^3+7x^2+5x+5\\ &&2x^3-2&\\ &&&7x^2+7x+7\\ &&&x^2+x+1 \end{matrix}


x31:x2+x+1x^3-1:x^2+x+1


x31x2+x+1x3+x2+xx1x2x1x2x10\begin{matrix} x^3-1 &&& |x^2+x+1 \\ x^3+x^2+x &&&x-1 \\ & -x^2-x-1\\ &-x^2-x-1\\ &&0 \end{matrix}


Then p(x)=x2+x+1p(x)=x^2+x+1 .


Q[x]/p(x)=Q[x]/<x2+x+1>Q[x]/p(x)=Q[x] /<x^2+x+1> .


The set Q[x]/p(x)Q[x]/p(x)  the product of polynomials from Q[x]Q[x] by p(x)=x2+x+1p(x)=x^2+x+1 .

We are obsessed with polynomials Q[x]Q[x] .

Then Q[x]/p(x)=Q[x]/Q[x]={0}Q[x]/ p(x)=Q[x]/Q[x]=\{0\}


It is not a field, because there  x2+x+1=0x^2+x+1=0


Answer: p(x)=x2+x+1p(x)=x^2+x+1 , Q[x]/IQ[x]/I is not a field


Need a fast expert's response?

Submit order

and get a quick answer at the best price

for any assignment or question with DETAILED EXPLANATIONS!

Comments

Assignment Expert
12.10.20, 21:59

Dear Ram, please use the panel for submitting new questions.

Ram
12.10.20, 18:45

Find the quotient field of integral domain {a+ib such that a,b belongs to Z}

Assignment Expert
08.10.20, 17:58

Dear Ram, please use the panel for submitting new questions.

Ram
08.10.20, 16:52

Find the quotient field of integral domain {a+ib such that a,b belongs to Z}

Ram
08.10.20, 16:48

If G is a group of even order, prove that it has an element 'a' which is not equal to 'e' satisfying a^2=e. e is identity element.

Ram
08.10.20, 16:40

Use fundamental theorem of homomorphism to prove that the ring R^2 and R^4/R^2 are isomorphic.

Ram
08.10.20, 16:37

Write down all elements of quotient group Z18/. Is any element of order 5?

LATEST TUTORIALS
APPROVED BY CLIENTS